Mechanical watch movement

ABSTRACT

Mechanical watch movement with an easily removable barrel mounted on an arbor with a friction coupling.

I United States Patent 1 1 1111 3,852,954 Bachmann Dec. 10, 1974 MECHANICAL WATCH MOVEMENT [56] References Cited [75] Inventor: Peter Bachmann, Bettlach, UNITED STATES PATENTS Switzerland 3,479,813 11/1969 Kocher 58/59 [73] Assignee: Ebauches Bettlach S.A., Canton of FOREIGN PATENTS OR APPLICATIONS Soleure, Switzerland 241,707 3/1946 Switzerland 58/59 22 F1 d: A 30 1974 1 l e pr Primary Examiner-George H. Miller, Jr. PP 465,580 Attorney, Agent, or Firm-Stevens, Davis, Miller &

' Mosher 1 [30] Foreign Application Priority Data May 11, 1973 Switzerland ..'....6731/73 [57] ABSTRACT W Mechanical watch movement with an easily removable [52] U S Cl I 58/59 5 8 /86 barrel mounted on an arbor with a friction coupling. ,[51] Int. Cl. G04b 33/00, GO4b 1/16 [58] Field of Search 58/59, 86, 138, 139 10 Claims, 3 Drawing Figures 1 MECHANICAL WATCH MOVEMENT This invention relates to a mechanical watch movement comprising a driving barrel held in place axially between two frame elements, a wheel-train connecting the barrel-drum to an escapement, and a dial-train connecting the barrel-drum to hourand minute-indicating members.

Watch movements arranged in this manner have been known for a very long time now. This arrangement makes it possible to reduce the total number of moving parts and, consequently, to simplify the construction of the movements. In order that the indicating members may be set to the correct time without disturbing the wheel-train and the escapement, a friction coupling must be provided between the dial-train and the barrel-drum. In certain known watch movements, the barrel cover has a hub on which the minute-wheel is engaged, being suitably fitted. The minute-wheel is therefore situated on the inner side of the baseplate, whereas in most of the conventional movements, it is situated on the outer side. Moreover, there are difficulties in producing a proper fitting between the hub of the cover and the minute-wheel when the movements have to be mass-produced and when it is desired to avoid as far as possible having to make corrections during assembly.

Driving-barrel arrangements are also known in which the barrel-arbor is detachable. This makes it simpler to overhaul the watch, for once the barrel-arbor has been extracted, the drum can be separated from the movement by a lateral displacement. Thus it is unnecessary to dismantle the barrel bridge. The use ofa driving barrel with a detachable arbor likewise enables the construction of the movement to be simplified since it is possible to providea wheel-train-and-barrel bridge in one piece and to attach this frame element to the baseplate, e.g., by means of pillars having their ends riveted to the frame elements. However, in the arrangements with detachable-arbor barrels known heretofore, the arbor is fastened to the frame. The part to which the inner end of the mainspring is hooked and the hub of the barrel-drum are both freely engaged on this arbor,

' and it is not possible to equip a barrel mounted in this manner with a member situated on the outer side of the movement and constituting the first moving part of the dial-train, which member is connected to the barreldrum by a friction coupling.

It is the object of the present invention to provide a mechanical watch movement of the type initially mentioned which. can be mass-produced efficiently and in which the various parts are arranged as simply as possible.

' A further, more particular object is to provide a driving-barrel arrangement comprising both a detachable arbor, enabling the production of a frame in which the frame elements are permanently attached to one another, and a dial-train separate from the wheel-train and comprising as a first member a moving part mounted on the outer face of the base-plate and driven by the barrel by means of a friction coupling.

To this end, there is provided according to the present invention a watch movement of the type initially mentioned wherein the barrel comprises an arbor passing through at least one of the said frame elements and having one end projecting over the outer side of the movement, a member of the said dial-train is fastened to the said projecting end of the barrel-arbor, and the arbor is connected to the drum by a friction coupling comprising a resilient bolt fixing the arbor axially to the drum.

In a preferred embodiment, the first member of the dial-train is a minute-wheel fixed on a square which the barrel-arbor possesses at the end of it situated toward the base-plate.

other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, taken in conjuction with the accompanying drawings, in which:

FIG. 1 is a top plan view of a preferred embodiment,

FIG. 2 is a section taken on the line II-II of FIG. I, and

FIG. 3 is a section on a larger scale through the arbor, showing a plan view of the bolt.

The watch movement shown in the drawing is designed so that it can be manufactured by the fastest and most efficient possible means. To this end, all the elements of this movement have been simplified, they have been reduced in number, and their form has been so chosen as to facilitate both their manufacture and their assembly.

As will be seen in FIG. 1, the mobement comprises a base-plate l, a barrel-and wheel-train bridge 2, a balance-cock 3, and betweem these frame elements, the members of the wheel-train, viz., a barrel 4 (FIG. 2), an eccentric center-wheel 5, a third wheel 6, a central fourth wheel 7, an escape wheel 8, a pallet 9, and an oscillating system with balance and balance-spring 10. The dial-train will be described further on.

The winding and setting mechanism comprises a sliding crown-wheel 11 which rests on the balance-cock 3, placed a little lower than the bridge 2, a stem 12 machined with a pinion toothing l3, and a setting-wheel (not shown in FIG. 1) which pivots on the lower face of the base-plate l. The stem is held in place by a resilient plate 14 which partly extends under the balancecock 3 and which is fastened around a cylindrical bearing surface of one of the pillars supporting the balancecock 3.

Whereas the balance-cock 3 is fastened on two pillars integral with the base-plate 1 by means of screws 15,

the bridge 2 is fastened to the base-plate lby three pillars 16a, 16b, which are riveted to the base-plate l and to the bridge 2, as can be seen in FIG. 2. The cylindrical ends of the pillars are engaged in circular openings cut out of the base-plate l and the bridge 2 and are then turned back laterally over the outer surfaces of those frame elements, thus ensuring the rigid and permanent attachment of those elements to the frame of the movement described.

As will be seen in FIG. 1, the base-plate 1 takes the form of a square with rounded corners. It is blanked according to the outline shown in the drawing and has in one of its straight sides a positioning notch 17 serving for various machining operations. The base-plate l is also lathe-turned so as to have projecting edges 18 which are formed out of part of its thickness and which serve to support the movement in the watch-case or on the fitting-ring. Holes 19 and 20 serve for the engagement and fastening of the dial-feet. It will be noted that they are situated in a region of the plate which is completely outside the central circular zone occupied by the parts of the movement and covered by bridges 2 and 3. This arrangement of the base-plate in itself makes possible a simplification of manufacture. For in order to fasten the base-plate on the lathe used to form the peripheral grooves of the edges 18, part-holders can be used which are adjusted to the distance between the parallel straight sides of the base-plate, no matter what the diameter of the rounding at the corners of the base-plate may be. These same part-holders may therefore be used for base-plates where the diameter of the rounding corresponds to calibers of various sizes. Thus, for example, the rounded corners of the base-plate 1 may be blanked and turned to dimensions corresponding to a 13" or a 12" caliber. The same wheel-trains and the same bridges will be used for both these calibers. If the diameter of the roundings of the base-plate isless than that shown in the drawing, i.e., if the roundings extends closer to the centers of the straight sides than is the case in the drawing, then holes 19 and 20 will be punched closer to the center.

The various punchings, blankings, and milling of the plate 1 will not be described here in detail inasmuch as these elements are for the most part conventional.

A square hole 21 in bridge 2 corresponds to two square holes in the base-plate 1, and these holes serve to fasten a partial stem cock on which the crown-wheel ll pivots. A similar partial stem cock 22 is held in place between a notch in the balance-cock 3 and a rectangular hole in the base-plate l in the vicinity of the straight side turned toward 3 oclock.

As will be seen in FIG. 2, the dial-train presents a particularity which greatly simplifies its manufacture. In this figure can be seen the pillar 16a which connects the base-plate l to the bridge 2, the central fourth wheel 7 with its spindle passing through a pipe 23 fastened to the center of the bsae-plate l, and the barreldrum 4. The latter has a toothing 24 which is engaged with the pinion of the eccentric center-wheel 5. The drum 4 is further provided with a tubular central hub extending inside the drum in the form of a cylindrical bushing 25, on the one hand, and outside the drum into the vicinity of the base-plate l in the form of a sleeve, on the other hand. The outer portion 26 ofa sleeve has an annular groove 27, the bottoom of which is broken through along a portion of its periphery so as to form a slot 27a. Engaged within the hub 25, 26 is a barrelarbor 28 fitted freely to the inside dimensions of the hub. Near its two ends, the arbor 28 passes through two openings 29 and 30 in the bridge 2 and in the base-plate 1, respectively, thus enabling the barrel 4 to pivot. At the level of the groove 27, the arbor 28 also has a groove 31 with a trapezoidal profile, in the bottom of which rests one of the arms of a bolt 32, the outer arm of which is engaged in the groove 27. This bolt 32, of a hairpin shape, forms a friction coupling between the arbor 28 and the barrel 4. At the same time, it fixes the arbor 28 axially. As the openings 29 and 30 have the same diameter as the opening of the hub 25, 26, the arbor 28 can thus slide axially and be removed. The bolt 32 is placed on the barrel 4 before the latter is fitted in the movement, and it resiliently presses the arbor 28 against the inner surface of the hub 25, 26. The inner edge of its arm which is in contact with the bottom of the groove 27 has a concave'rounding, while the inner edge of the other arm is straight and rests against the arbor 28 through the opening in groove 27.

At its upper end, the arbor 28 has a frustoconical head 33 provided with a slot. It can be grasped by this head and extracted from the movement, thus enabling the barrel 4 to be removed laterally for repair or overhaul.

Engaged on the bushing 25 which extends inside the drum 4 is a tubular core 34. It is provided with a stophook 35 for the inner end of the mainspring, and a ratchet-wheetl 36 is driven onto the upper end of it. Thus the ratchet-wheel 36 acts as a cover for the barrel 4 and extends immediately beneath the bridge 2. The length of the core 34 is very slightly less than that of the bushing 25 which, with the sleeve 26, determines the axial shake of the barrel assembly on arbor 28.

At its lower end, the arbor 28 has a square 37 which projects from the outer face of the base-plate l in a thinner portion of this frame element. The square 37 serves as a connection element between the arbor 28 and a minute-wheel mounted on the outer face of the base-plate 1. This minute-wheel is composed of a pinion 38 and a toothed disc 39. The pinion 38 is made by blanking from a circular disc with a square center hole adjusted to the dimensions of the square 37. It has a peripheral toothing which will be machined, preferably by milling, and as seen in the drawing, it has teeth truncated at approximately half of their height and limited by outer faces contained in an imaginary circular cylindrical surface. The toothed disc 39 has a center opening adjusted to the dimensions of this imaginary cylindrical surface, and it is driven onto the pinion 38. Since it is thinner than the pinion 38, it leaves a sufficient portion of the thickness of the teeth alongside it to ensure the meshing of the pinion 38 with an hour-wheel 41, as will be seen in the drawing.

The hour-wheel 41 is itself mounted on a cannonpinion 40 which pivots on the pipe 23 and meshes with the peripheral toothing of the disc 39.

This arrangement makes it possible to use a baseplate in which the differences in height between the various zones are reduced to the minimum. Thus the minute-wheel is fitted in a recess in the outer face of the base-plate. It is completely sunk into this recess through the bottom of which the arbor 28 passes, which enables the barrel to pivot in the base-plate. Since the friction coupling necessary for setting exists between the arbor 28 and the drum 4, the minute-wheel is driven directly by the barrel-arbor owing to the rigid coupling composed of the square hole of the pinion 38 and the corresponding square at the end of the arbor 28. This indirect drive of the hands requires a minimum number of parts, and the arrangement described makes it easy to dismantle both the barrel and the timeindicating members.

The toothed disc 39 will be engaged with a settingwheel, likewise pivoting on the outer face of the baseplate and cooperating with the member of the setting mechanism.

In the event that the movement described is to be constructed to receive hourand minute-indicating members consisting of discs extending beneath the dial and partially appearing in an aperture, instead of the usual hands moving above the dial, the same constituent elements of the minute-wheel may be used. However, the pinion 38, rather than being milled with all its teeth truncated, will have a certain number of full teeth regularly distributed around its periphery. The outside diameter of the toothing of the hour-wheel will be slightly less than in the case described above, so that only the full teeth of the minute-hweel pinion mesh 5. with its toothing. The hour-wheel will normally be kept me fixed position, e.g., by a jumper-spring, and will move by one-twelfth of a revolution per hour, driven by one of the full teeth of the minute-wheel pinion.

In this case, the center opening of the disc 39 will be blanked with notches corresponding to the full teeth of the pinion 38 so that this disc may be driven onto the pinion. Provision might also be made to let the full teeth of the pinion 38 remain only for a portion of their thickness, the disc 39 then having a circular opening driven onto the portions of truncated teeth. This simplified minute-wheel drives the moving parts 40 and 41 under conditions corresponding to conventional conditions. In particular, despite the fact that the teeth of the pinion 38 are truncated for about half of their height, an hour-wheel with a conventional toothing, such as wheel 41, meshes with them perfectly.

The arrangement of a click 42 for retaining the ratchet-wheel 36 can be seen in FIG. 1. The click 42 is a blanked flat plate having an indentation 43 in the form of an arc of about 220 along one of its edges. On the edge of it opposite the indentation 43, the plate 42 has a beak 44 which is slightly inclined with respect to the radial direction determined by the center of the indentation 43 and the end of the beak 44. Two wings, 45 and 46, extend on either side of this beak 44, the wing 46 being limited by a straight edge which comes to test against the toothing of the ratchet-wheel 36, while the wing 45 extends beyond the edge of the bridge 2.

As will be seen in FIG. 2, the pillar 16a has a first shoulder 47 which serves to position the bridge 2 with respect to the base'plate l and, starting at the edge of this shoulder 47, a cylindrical bearing surface 48 limited axially by a second shoulder 49. It is on the cylindrical bearing surface 48 that the indentation 43 of the click 42 is engaged, so that the latter is held axially in place between the inner face of the bridge 2 and the shoulder 49. The beak 44 is engaged in the toothing of the ratchet-wheel 36, and normally, the action of the mainspring presses the wing 46 against this same toothing, so that the ratchet-wheel 36 is blocked. However, if pressure is applied to the wing which projects beyong the bridge 2, the beak 44 is disengaged from the toothing of the ratchet-wheel 36, which allows the mainspring to be let down.

Upon winding, when the stem 12 is turned so that the crownwheel ll is driven counterclockwise as viewed in H6. 1, this wheel 11 comes to mesh with the toothing of the ratchet-wheel 36 and turns it clockwise. The click 42 pivots so that the beak 44 leaves the toothing. it is then returned by a spring consisting of an arm 50 blanked in the resilient plate 14 and resting on the end of the indentation 43 situated on the same side as the wing 46.

A hole 51 made in the bridge 2 makes it possible to verify whether the click is in place and whether it is properly resting against the ratchet-wheel.

The arrangement of the click 42 which has just been described considerably simplifies the manufacture of the movement for several reasons. First of all, whereas the conventional clicks are generally held in place by a step-screw, the click described here pivots around a cylindrical bearing surface which is lathe-turned directly in one of the pillars of the movement. Thus the manufacture of a part is avoided, and above all, of a threaded part. Moreover, the production of a clickwith an indentation in the shape of an arc of more than 180 requires vastly simpler tooling than that of a click having a hole. Clicks must be made of steel in order to prevent them from wearing out too quickly, and the diameter of the pivot is obviously very small. The tools required for blanking and punching steel plates with a small-diameter hole are extremely delicate and, consequently, highly subject to breakage, as well as being very expensive. The manufacture of a blanking tool having the necessary shape for producing the click 42 is much less expensive, and this tool is much sturdier than one having a punch for cutting out a hole. The tooling costs for manufacturing the click 42, as well as the rejects, are therefore considerably reduced with the arrangement shown in the drawing. Finally, it will be noted that the movement described does not necessitate the manufacture and fitting of a special spring for the click since this spring is blanked in one piece with the one which holds the winding-stem in place. This plate, made of beryllium bronze, for example, performs two functions, and it, too, is very simple to fit in place.

What is claimed is:

l. A mechanical watch movement comprising a driving barrel held in place axially between two frame elements, a wheel-train connecting the barrel-drum to an escapement, and a dial-train connecting the barreldrum to hourand minute-indicating members, wherein the barrel comprises an arbor passing through at least one of the said frame elements and having one end projecting over the outer side of the movement, a member of the said dial-train is fastened to the said projecting end of the barrel-arbor, and the arbor is connected to the drum by a friction coupling comprising a resilient bolt fixing the arbor axially to the drum.

2. A watch movement in accordance with claim I, wherein the resilient bolt consists of a part independent of the arbor and of the drum, said part being detachable.

3. A watch movement in accordance with claim 1, wherein the said member of the gear-train connecting the drum to the indicating members is a minute-wheel.

4. A watch movement in accordance with claim 3, wherein the barrel-arbor passes through the said two frame elements, the projecting end of said arbor has a non-circular section engaged in an opening of corresponding shape in the minute-wheel, and the other end of the arbor has a hooking-stud for extracting said arbor.

5. A watch movement in accordance with claim 1, further comprising a ratchet-wheel extending between the said frame elements and a sleeve for hooking the inner end ofa mainspring, wherein the said sleeve is engaged on the inner portion of the hub of the barrel, and the ratchet-whee] is fixed to one end of said sleeve.

6. A watch movement in accordance with claim 5, wherein the ratchet-wheel constitutes the cover of the barrel.

7. A watch movement in accordance with claim 1, wherein the barrel-drum comprises a central hub, one portion of said hub extending inside the drum and another portion of said hub extending between the drum and one of the said frame elements, and the said resilient bolt is mounted on the said other portion of the hub.

8. A watch movement in accordance with claim 7, wherein the said other portion of the hub has a slot, the

wherein the said other portion of the hub has a groove in which the said slot is contained.

10. A watch movement in accordance with claim 8, wherein the flanks of said groove of the arbor are inclined with respect to the axis of the arbor. 

1. A mechanical watch movement comprising a driving barrel held in place axially between two frame elements, a wheel-train connecting the barrel-drum to an escapement, and a dial-train connecting the barrel-drum to hour- and minute-indicating members, wherein the barrel comprises an arbor passing through at least one of the said frame elements and having one end projecting over the outer side of the movement, a member of the said dial-train is fastened to the said projecting end of the barrel-arbor, and the arbor is connected to the drum by a friction coupling comprising a resilient bolt fixing the arbor axially to the drum.
 2. A watch movement in accordance with claim 1, wherein the resilient bolt consists of a part independent of the arbor and of the drum, said part being detachable.
 3. A watch movement in accordance with claim 1, wherein the said member of the gEar-train connecting the drum to the indicating members is a minute-wheel.
 4. A watch movement in accordance with claim 3, wherein the barrel-arbor passes through the said two frame elements, the projecting end of said arbor has a non-circular section engaged in an opening of corresponding shape in the minute-wheel, and the other end of the arbor has a hooking-stud for extracting said arbor.
 5. A watch movement in accordance with claim 1, further comprising a ratchet-wheel extending between the said frame elements and a sleeve for hooking the inner end of a mainspring, wherein the said sleeve is engaged on the inner portion of the hub of the barrel, and the ratchet-wheel is fixed to one end of said sleeve.
 6. A watch movement in accordance with claim 5, wherein the ratchet-wheel constitutes the cover of the barrel.
 7. A watch movement in accordance with claim 1, wherein the barrel-drum comprises a central hub, one portion of said hub extending inside the drum and another portion of said hub extending between the drum and one of the said frame elements, and the said resilient bolt is mounted on the said other portion of the hub.
 8. A watch movement in accordance with claim 7, wherein the said other portion of the hub has a slot, the barrel-arbor has an annular groove situated at the level of the said slot, and the said bolt is a U-shaped part, one of the arms of said bolt resting on the said other portion of the hub, and the other arm of said bolt being engaged in the said groove.
 9. A watch movement in accordance with claim 8, wherein the said other portion of the hub has a groove in which the said slot is contained.
 10. A watch movement in accordance with claim 8, wherein the flanks of said groove of the arbor are inclined with respect to the axis of the arbor. 